<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="./styles/index.css" />
    <title>Document</title>
  </head>
  <body>
    <div id="app" class="score-case">
      <div class="table">
        <table>
          <thead>
            <tr>
              <th>编号</th>
              <th>科目</th>
              <th>成绩</th>
              <th>操作</th>
            </tr>
          </thead>
          <tbody>
            <tr v-for="(v,i) of list" :key="v.id">
              <td>{{ i+1 }}</td>
              <td>{{ v.subject}}</td>
              <td :class="{red:v.score<60}">{{ v.score }}</td>
              <td><a href="#" @click="del(v.id)">删除</a></td>
            </tr>
          </tbody>
          <tbody v-show="list.length === 0">
            <tr>
              <td colspan="5">
                <span class="none" v-show="list.length===0">暂无数据</span>
              </td>
            </tr>
          </tbody>

          <tfoot>
            <tr>
              <td colspan="5">
                <span>总分：{{ totalScore }}</span>
                <span style="margin-left: 50px">平均分：{{ average }}</span>
              </td>
            </tr>
          </tfoot>
        </table>
      </div>
      <div class="form">
        <div class="form-item">
          <div class="label">科目：</div>
          <div class="input">
            <input  v-model.trim="subject" type="text" placeholder="请输入科目" />
          </div>
        </div>
        <div class="form-item">
          <div class="label">分数：</div>
          <div class="input">
            <input  v-model.trim.number="score" type="text" placeholder="请输入分数" />
          </div>
        </div>
        <div class="form-item">
          <div class="label"></div>
          <div class="input">
            <button class="submit" @click="add">添加</button>
          </div>
        </div>
      </div>
    </div>
    <script src="../vue.js"></script>

    <script>
      const app = new Vue({
        el: "#app",
        data: {
          list: [
            { id: 1, subject: "语文", score: 20 },
            { id: 7, subject: "数学", score: 99 },
            { id: 12, subject: "英语", score: 70 },
          ],
          subject: "",
          score: "",         
        },
        computed: {
          totalScore(){
          return this.list.reduce((sum,v)=>sum+v.score,0)
          },
          average(){
        return (this.totalScore/this.list.length).toFixed(2)
          },},
          methods:{
          add() {
            this.list.push({
              id: Date.now(),
              subject: this.subject,
              score: this.score,
            });
            this.subject='',
            this.score=''
          },
          del(id) {
            const i = this.list.findIndex((v) => v.id === id);
            this.list.splice(i, 1);
          },
        },   

      });
    </script>
  </body>
</html>
